Oil lubricating formulations such as crank case oils are easily contaminated with water and acids created during combustion. Accordingly water compatibility and pH stability are important properties. In addition, improved detergent capabilities and the reduction of friction. The significance of these properties is most important under severe conditions such as when lubricants come into contact with water under the extreme pressure and temperature conditions during combustion.
In connection with crank case oils, it is particularly important to maintain engine cleanliness and frictional resistance in order to keep engine parts clean and reduce fuel consumption.
If acceptable water tolerance properties and pH levels are not maintained, lubricants will develop reduced power transmission properties and cause corrosion of the engine parts. Fluid flow is not smooth when water separates out and the separated water can be vaporized to steam at high temperature. These properties are particularly important in connection with functional fluid compositions.
Manufacturers of equipment requiring the use of functional fluids and lubricants often require that such fluids and lubricants process specific water tolerance and/or stability properties. For example, manufacturers of agricultural tractor machinery have specific requirements with respect to the water tolerance properties of tractor fluids used in connection with the machinery which the manufacturer believes to be necessary for the equipment to operate successfully under severe conditions. Low pH levels in an engine oil can greatly increase engine corrosion.
Fluids with poor water tolerance properties becomes turbid and the clarity of functional fluids often impacts greatly on the fluid's marketability. A fluid that is turbid or becomes turbid after a short period of use is often unacceptable to consumers regardless of the performance characteristics of the fluid. Improved clarity not only increases marketability but allows the user to more readily and accurately determine when the fluid should be replaced. A combination of poor water tolerance and low pH can be particularly damaging to performance.
U.S. Pat. No. 4,579,672 discloses functional fluids and lubricants having improved water tolerance properties. The compositions are comprised of major amounts of a synthetic or mineral oils of lubricating viscosity with minor amounts of oil soluble alkoxypolyethyleneoxy acid phosphite ester compounds dispersed therein as the water tolerance improving compounds.
U.S. Pat. No. 3,791,971 discloses polyoxyalkylene glycols and their reaction products with organic diisocyanate and dicarboxylic acid. These reaction products are combined with alkaline earth metal carbonates and dispersed in a hydrocarbon medium to provide lubricating compositions which are indicated as having superior acid neutralization capability and rust inhibiting properties when used within internal combustion engines. A number of compounds are disclosed throughout the 3,791,971 patent such as those encompassed by the general structural formulation shown at column 2, lines 44-55.
U.S. Pat. No. 4,265,774 discloses high molecular weight polygylcerol derivatives which are indicated as being useful as thickening agents for water-based lubricants. A large number of compounds encompassed by the general structural formula as shown at column 1, lines 35-45 are disclosed.
U.S. Pat. No. 3,625,893 discloses lubricating oil compositions which include minor amounts of basic group II metals salts of carboxylic acids and napthenic acids. The oil compositions including the additives are indicated as having improved oxidation stability and antirust properties.
U.S. Pat. No. 4,088,590 discloses brake fluids and operating fluids for central hydraulic installations in motor vehicles which are indicated as having excellent temperature/viscosity behavior as well as good lubricating properties. The improved properties are indicated as being obtained by including additives in the form of polyethylene glycol alkyl ether-based fluids of alkyl polyethylene glycol-t-butyl ethers. Amounts of the additive and a structural formula encompassing the additive is shown within the 4,088,590 patent at column 1, lines 7-19.
U.S. Pat. No. 3,856,688 discloses multi-purpose grease compositions which include thickening agents in the form of dibasic fatty acid soap compounds. The general structural formula of the dibasic fatty acid soap compounds utilized as the thickening agents is disclosed within the patent at column 1, line 60 with the variables defined thereafter.
U.S. Pat. No. 3,828,086 discloses dibasic fatty acid soap compounds which can be utilized as thickening agents. The general structural formula of the dibasic fatty acid soap compositions is disclosed in the patent at column 2, line 10 and defined thereafter.
U.S. Pat. No. 2,801,972 discloses stable lubricating greases which are prepared by incorporating into lubricating oils a grease thickener. The grease thickener is obtained by fusing high molecular weight ether derivatives having a primary alcohol group with an alkali, particularly caustic soda or pot ash. The general structural formula of the ether alcohols indicated as being useful in connection with the invention is given in the patent at column 2, line 45 and defined thereafter.
The U.S. parent application, serial number 07/020/287, filed February 27, 1987 upon which the present application is claiming priority was filed as a PCT application on Feb. 19, 1988 which application was published on Sept. 7, 1988 as W088/06615.
The present inventors have discovered that improved functional fluids and lubricating compositions such as crank case oils can be obtained by combining major amounts of an oil of lubricating viscosity with a minor amount of an additive component. In this limited respect, the present invention relates to the same general concept which is being carried out in the patents discussed above. However, the compounds which the present inventors utilize as the additive component is structurally different from and chemically distinct from the compounds referred to in the above-discussed patents. Although some of the compounds per se utilized by the present inventors to improve performance properties of compositions may not be completely novel compounds per se, such compounds as included within the oil compositions are novel compositions.
Sandoz Product Bulletin 7-200/85 refers to a number of surfactant compounds sold under the trademark Sandopan. These compounds generally conform to the formula: EQU R-O-(C.sub.n H.sub.2n O).sub.m R.sub.1 COOX
where R is a fatty group containing 13 to 18 carbons, n is 2 to 4, m is 1 to 100, R.sub.1 is CH.sub.2 to C.sub.3 H.sub.6 and X is H or Na. These compounds are indicated as being useful in products such as cleaning fluids, cosmetics and toiletries.